Forty years ago today — on Sept. 30, 1968 — the first Boeing 747 jumbo jet rolled out of the company’s new factory in Everett. Thousands turned out at the ceremony to marvel at the giant new plane with a wingspan of 196 feet and a tail that was six stories high.

Capable of carrying more than 400 passengers, the first 747 was two and a half times bigger than the largest jets then in service: the Boeing 707 and Douglas DC-8.

Chief 747 engineer Joe Sutter, in his book “747″ that recounted the story of the airplane’s development, recalled that the plane was not quite ready for rollout that day.

“Fortunately … we came up with four presentable engines to hang on it so that it looked complete from the outside,” Sutter wrote.

The 747 was designed and built in record time.

Pan American World Airways placed the first $525 million launch order for 25 Boeing 747s in April 1966. To build a jet so much bigger than any before, Boeing had to build a new factory, which would become the largest building by volume in the world. Construction of the Everett plant began in June 1966, and the walls of the building went up as the assembly lines were laid down.

The 747 flew for the first time just four months after rollout, on Feb. 9, 1969.

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